This was a script I developed for my portfolio. I think you guys will like it a lot. It adds a 'Bolt' primitive to your 'Extended Primitives' pulldown in the command panel for 3d studio max. It's stable, and includes lots of cool features like head-cuts, height and radius of both the head and the body, and segments. In this latest version, you can even edit some parameters of the head cut like width, depth, and more.

Note that this creates procedural objects, and as such, I haven't built in any threads. With these objects you have the choice of building them as geometry or in the materials, so this script is well suited for low poly work too.

The link below has a demo .max file (Max 9) where you can see some example bolts from the script!